1. Field
The present disclosure relates to an injection molding apparatus that is used to produce injection products in an injection machine. More particularly, the present disclosure relates to a slim injection molding apparatus whose height is reduced by removing an upper pushing plate and a lower pushing plate for ejecting injection products.
2. Description of Related Art
As illustrated in FIG. 1, a conventional injection molding apparatus 2000 is formed such that a spacer block 2131 is disposed below a lower molding plate 2111, and a pushing plate 2141 that can move upward and downward is disposed inside the spacer block 2131. Also, the pushing plate 2141 is provided with a plurality of pushing pins 2142 configured to pass through a lower core 2113 disposed on the lower molding plate 2111 and to push an injection product.
Accordingly, after an injection operation forming an injection product in a cavity 2101 and cooling the injection product are completed, when ejecting the injection product, an upper molding plate 2121 moves in a direction away from the lower molding plate 2111 so as to open the cavity 2101 formed by an upper core 2123 and the lower core 2113. After that, the pushing plate 2141 is moved, and thus the injection product is separated from the lower core 2113 by the pushing pins 2142 provided in the pushing plate 2141.
However, since the conventional injection molding apparatus 2000 uses the upper molding plate 2121, the lower molding plate 2111, the spacer block 2131, and the pushing plate 2141, there are problems that the overall size of the molding apparatus is large and material cost and processing cost thereof are expensive.
Also, in order to increase productivity of the injection molding apparatus tandem injection molding apparatuses or stack injection molding apparatuses that can produce two injection products by using two cavities formed in a single injection molding apparatus are used.
Since the tandem injection molding apparatus is configured such that an injection process is performed in one cavity while a formed injection product is cooled in the other cavity, the injection products may be continuously produced so that the productivity may be increased.
However, in a conventional tandem injection molding apparatus 3000, as illustrated in FIG. 2, a spacer block 3131 is disposed below each of a first lower molding plate 3111 and a second lower molding plate 3112, and a pushing plate 3141 that can move upward and downward is disposed inside each of the spacer blocks 3131. Also, the pushing plate 3141 is provided with a plurality of pushing pins 3142 that pass through a lower core 3113 of each of the first lower molding plate 3111 and the second lower molding plate 3112 and push injection products.
Accordingly, after an injection operation forming an injection product in a cavity 3101 and cooling of the injection product are completed, when ejecting the injection product, the first lower molding plate 3111 or the second lower molding plate 3112 moves in an opposite direction from the first upper molding plate 3121 or the second upper molding plate 3122 so as to open the cavity 3101 formed by an upper core 3123 and a lower core 3113. After that, the pushing plate 3141 is moved, and thus the injection product is separated from the lower core 3113 by the pushing pins 3142 disposed in the pushing plate 3141.
However, the conventional tandem injection molding apparatus 3000 needs the two spacer blocks 3131, the two pushing plates 3141, and a plurality of pushing pins 3142 in order to eject the injection product so that a height H of the conventional tandem injection molding apparatus 3000 is high. Accordingly, it is difficult to use the conventional tandem injection molding apparatus in normal injection machines using a normal injection molding apparatus. Therefore, the conventional tandem injection molding apparatus needs a special injection machine having a mold opening distance longer than that of the normal injection machines.